I have been making a Guess My Number game, and I was seeing what would happen if I changed some of my answers a little, so for difficulty I put 'n', instead of the 1, 2 or 3 that I should normally use. It then set itself on an infinite loop for some apparently unexplained reason.
It will do that as its expecting a numeric value and your giving it a ascii character. You should also try and avoid goto statements, not good practice - use a do..while to make sure they enter within the range required so you dont need that nasty goto statement ;-)
Anyway, to get around the loop issue just read in a character and test that instead of an int.